1. Field of the Invention
The present invention relates to an optical scanning device, and more particularly to an optical scanning device with a dustproof function used in a scanner, an electrograph or the like.
2. The Related Art
Nowadays, an image manipulation device such as a scanner, an electrograph or the like is widely used by people in their daily life and work. The image manipulation device is provided with an optical scanning device for getting image information and further inputting the image information into a computer.
Referring to FIG. 1, a conventional double-side scanning device 30 is shown. The double-side scanning device 30 includes a lower cover 301 and an upper cover 302. A first optical mechanism 5 is disposed beneath the lower cover 301 and a second optical mechanism 6 is disposed above the upper cover 302. The first optical mechanism 5 and the second optical mechanism 6 respectively include a shell 51, 61. The shell 51, 61 defines a receiving room 511, 611 for accepting an optical scanning module 52, 62 and a window 512, 612 for scanning light beams passing therethrough. The lower cover 301 and the upper cover 302 respectively mount a glass platform 53, 63 thereon facing the window 512, 612. Two correcting plates 54, 64 are respectively arranged on the upper cover 302 and the lower cover 301 for correcting the image white of the first and second optical mechanisms 5, 6. The correcting plate 54 disposed on the upper cover 302 faces the glass platform 53 mounted on the lower cover 301 and the window 512 defined on the shell 51 of the first optical mechanism 5. The other correcting plate 64 disposed on the lower cover 301 faces the glass platform 63 mounted on the upper cover 302 and the window 612 defined on the shell 61 of the second optical mechanism 6.
It can be seen that the glass platforms 53, 63 are formed apart from the shells 51, 61. Therefore, when the double-side scanning device 30 is assembled, and especially when the first optical mechanism 5 is disposed beneath the lower cover 301 and the second optical mechanism 6 is disposed above the upper cover 302, the suspending dust is easy to fall in the receiving rooms 511, 611 of the shells 51, 61 and attach to the optical scanning modules 52, 62, which brings a bad influence on the scanning quality of the double-side scanning device 30. For example, straight stripes are easily formed on the image. Besides, because the two correcting plates 54, 64 are respectively arranged on the upper cover 302 and the lower cover 301 to cooperate with the first and second optical mechanisms 5, 6, the first and second optical mechanisms 5, 6 have a far distance therebetween along the scanning direction, so that a short document is hard to be scanned, which limits the use of the double-side scanning device 30. Furthermore, because the glass platforms 53, 63 are correspondingly mounted on the lower cover 301 and the upper cover 302, and the lower cover 301 and the upper cover 302 are respectively fixed, then the vertical distance between the lower cover 301 and the upper cover 302 is decided and hard to be adjusted, so the double-side scanning device 30 just scans a document with special thickness.